Filament for incandescent-gas-lamp mantles.



RENE LAIG-LE, 0F PARIS, FRANCE.

FILAMENT FOR, INCLANDESGENT -GAS-LAMP MANTLES.

No Drawing.

To all whom it may concern:

Be it known that I, Benn LAreLn, citizen of France, residing at Paris,in the Republic of France, have invented new and useful Improvements inFilaments for Incandescent-GasLamp Mantles, (for which a French patenthas been filed October 11, 1907,) of which the following is aspecification.

This invention has for its object the pro duction of an infusible andindestructible filament intended for the manufacture of mantles forincandescent gas lamps. This object is effected by mixing certain OXlClSof the rare earths such as those of thorium, cerium and the like, withanother oxid, such as the oxid of beryllium, which has a lower meltingpoint than that of such earthy mate rial, though it may be infusibleexcept at very high temperatures. I add to this mixture alumina andsilica with enough of the active principle of some agglutinant gum toconvert it into a pasty mass, from which filaments may be successivelydrawn by means of a draw plate. Such a filament has suf ficientconsistency and rigidity to be subjected without fear of deteriorationto the temperature which it is necessary for it to undergo.

As an example I give the following:

Alumina precipitated by ammonla 3 parts ()Xid of beryllium 2 Silica orsilicate of alumina 1 ()Xid of thorium 92. 8 Oxid of cerium 1. 20

Specification of Letters Patent.

Application filed December 31, 1907.

Patented Aug. 9, 1910.

Serial No. 408,802.

will be aided by the silica and alumina. Thorium and cerium are notmentioned to the exclusion of other highly refractory earths of likenature and attributes capable of serving as their substitutes andequivalents; and of course the oxid of either one of the rare earthsabove mentioned or of such equivalent may be used, instead of dividingthe amount of rare earth oxid between two of them. But I prefer thecomposition filament stated.

Instead of supplying oxid of beryllium to the mixture before heating Imay supply the metal beryllium, which will be oxidized in the heatingprocess long before reaching the fusing point of its oxid therebyproduced.

Having thus described my invention, what I claim new and desire tosecure by Letters Patent is:

1. A filament consisting of oXid of thorium ninety two and eight tenthsper cent, oxid of cerium one and two tenths per cent. and inertauxiliary matter six per cent.

2. The process of manufacturing filaments consisting in the followingsteps; first mixing a highly refractory oXid of rare earth, such asthorium, with material, such as oxid of beryllium, which is also highlyrefractory but has a lower point of fusion than such earthy oxid, andsupplementalmaterial,such as silica and alumina, and converting thismixture into a pasty mass by adding agglutinant gum; secondly drawingsuch mass out into filamentary form; thirdly, subjecting the filamentsthus formed to a regular intense long continued heat sufficient to meltat last the OXlCl of beryllium and convert it at last into a bindingagent for the oxid of thorium while keeping said filament perfect inform and constitution substantially as set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

RENE LAIGLE.

lVitnesses JULns FAYOLLET, Eueimn PIcHoN.

